Question

How to find the geometrical isomers of the given compound,and also how many geometrical isomers does the compound have?

Answer 1

There isn't any formula for structural isomers. But there are formulas for stereo isomers. If there are n chiral carbons in a molecule, then the following two cases may arise:

Case 1: The ends of the molecule are asymmetric. In this case, the number of structural isomers is $2^n$ and all of them are optically active.

Case2: The ends of the molecule is symmetric. Following two cases may arise:

Case 2a: n is even. In this case number of optically active form =2(n -1). The number of meso isomers is $2^{(}0.5n-1)$ and the total number of stereoisomer is the summation of these two.

Case 2b. n is odd. In this case, total number of stereoisomer is 2^(n -1). The number of meso isomers is $2^{(}0.5n-0.5)$ and the number of optically active forms is the difference of these two.